Fix render issue

Author: JialinXin

articles/azure-web-pubsub/tutorial-serverless-notification.md

@@ -437,6 +437,8 @@ In this tutorial, you learn how to:
         </body>
     </html>
     ```
+    
+    # [JavaScript](#tab/javascript)
 
     # [C#](#tab/csharp)
     Since C# project will compile files to a different output folder, you need to update your `*.csproj` to make the content page go with it.
@@ -447,6 +449,8 @@ In this tutorial, you learn how to:
         </None>
     </ItemGroup>
     ```
+    
+    # [Python](#tab/python)
 
 7. Configure and run the Azure Function app